MAINTAINERS: update @philips email
MAINTAINERS: update @philips email

Brandon is no longer at Red Hat. Use a different email.

dannysauer/etcd,etcd-io/etcd,mkumatag/etcd,mkumatag/etcd,cockroachdb/etcd,mqliang/etcd,li-ang/etcd,coreos/etcd,mqliang/etcd,gyuho/etcd,etcd-io/etcd,cockroachdb/etcd,gyuho/etcd,rnaveiras/etcd,rnaveiras/etcd,etcd-io/etcd,coreos/etcd,dannysauer/etcd,ajityagaty/etcd,rnaveiras/etcd,li-ang/etcd,ajityagaty/etcd,mqliang/etcd,mkumatag/etcd,ajityagaty/etcd